Looking at the first picture, your leaf looks particularly healthy. However, it's a bit hard to judge the plant's overall health under your grow lights. Would you mind showing us some images of the whole plant in natural light?
I had it in the grow tent since then I have taken it out due to it getting sunburnt a bit. But here is the plant and leaf. It had a few leaves with smaller variegation which I'm trying to propagate aswell but this had the most so I cut it back to the node to encourage it to variegate more from here. So @MitchellMc what's your prognosis.
How long ago did you cut it back to the node, and what does your watering regime comprise? It's looking relatively healthy apart from the obvious sunburn that you've picked up on. It appears you have some well-draining mix there, and it would need adequate watering to keep up with the mix drying out. Perhaps you might like to place a shallow saucer under it to keep some additional moisture in the pot.
I'd suspect sunburn either direct through the grow tent or through water sitting on the leaf, especially if it's the top of the plant where it is most exposed. I don't think it is disease. It looks more like damage of some sort, most likely sun.
I took it out of the sun. I've let the medium dry out a bit as it looked a bit wet hopefully this will help. Thanks again